The invention of the snowmobile naturally gave rise to a need for reliable transportation of snowmobiles hither and yon, and the same can be said for other ski-type vehicles, such as the jet-ski. Recognizing that these ski-type vehicles are often transported to remote areas under less than ideal road conditions, a transport device for such vehicles should be durable as well as reliable. Further recognizing that snowmobiles, in particular, are often loaded and unloaded in very cold weather, a snowmobile transport device should also be convenient to operate regardless of the weather conditions. As discussed below, others have attempted to address the need for such a transport device, but with only limited success.
U.S. Pat. No. 3,885,690 to Van Slambrouck discloses a snowmobile trailer that is designated as 10 and labeled as "Prior Art" in FIGS. 1 and 2 herein. The trailer 10 includes hold down rods 40 that extend from either of two side rails 32 to an intermediate bracket 38 mounted on the trailer bed 28. The rods 40 are secured in place by means of cotter pins 48, or alternatively, by threading the ends of the rods 40 into holes 44 formed through the intermediate bracket 38. The more accessible end of each rod 40 is bent at a right angle relative to the length of the rod to provide a crude handle 46 for grasping the rod.
The shortcomings of the Van Slambrouck device include the manner in which the hold down rods are locked relative to the side rails and brackets. In this regard, the insertion and removal of cotter pins is cumbersome, particularly in very cold weather. The alternative of threading the distal end of the rod through a hole in the bracket is also cumbersome in cold weather, and even more so once ice, rust, or other debris has accumulated on the distal end of the rod and/or within the hole through the bracket.
U.S. Pat. No. 4,281,950 to Lehman et al. discloses a wheelbarrow trailer having a pair of T-shaped hold down bars that cooperate with a pair of dual slot brackets. In a first locked position, the stem of the T-shape occupies a first slot, and the cross member of the T-shape does not extend across a wheelbarrow leg. In a second locked position, the stem occupies a second slot, and the cross member of the T-shape does extend across a wheelbarrow leg. A quarter turn of either bar about the axis of the cross member rotates the stem of the T-shape out of engagement with either of the slots to allow axial movement of the bar relative to the slots and the wheelbarrow leg.
The Lehman et al. retention system is designed for transport of a wheelbarrow at relatively low speed and across relatively flat terrain (note the small wheel base of the trailer wheels). No provision is made for positively locking the hold down bars in the second slots. Thus, the Lehman et al. retention system is not well suited for transport of ski-type vehicles at highway speeds and/or across uneven terrain.
U.S. Pat. No. 5,044,845 to Baker, Jr. discloses a snowmobile trailer having a hold down bar that extends across an intermediate portion of the trailer bed. A plurality of hooks extend up through the bed of the trailer to capture the bar, and spring loaded levers bias the hooks downward to retain the bar.
The Baker, Jr. retention system has moving parts and requires significant modification of most, if not all, conventional types of trailers used to transport snowmobiles and the like. The moving parts introduce significant additional expense into the manufacturing costs and require relative precise positioning of the bar relative to the snowmobile and the trailer in order to function according to design. The moving parts are also susceptible to seizure and/or failure after extended exposure to the elements and extreme weather conditions.
U.S. Pat. No. 5,203,655 to Persau discloses a snowmobile trailer having a hold down bar that extends across an intermediate portion of the trailer bed. The bar is secured in place by means of a bolt that is threaded into a hole formed through the trailer bed.
The Persau retention system requires an alignment of parts that is cumbersome, particularly in very cold weather. Also, after extended exposure to the elements and inclement weather, the threaded bolt assembly is susceptible to rusting and/or freezing in a locked configuration or at least to the extent that it becomes difficult to operate.
As is evident from the foregoing discussion of the Prior Art, a need remains for a snowmobile transport device that is convenient to operate and both reliable and durable in use. An object of the present invention is to provide such a device for the transport of snowmobiles and other ski-type vehicles. Another object of the present invention is to provide a retention system for snowmobiles and the like that is simple in construction, as well as in use, and that requires minimal modifications to existing trailers. These and other objects of the present invention will become apparent upon a detailed description of a preferred embodiment.